Acute lower respiratory infections (ALRI) are a common cause of illness globally and it is estimated to be the third common cause of death, approximately 7% of all deaths in 2004. In Ghana, where infectious diseases including respiratory infections, constitute more than 40% of all deaths in the country, there is little or n data on the epidemiology of ALRI and almost all febrile episodes are treated as malaria. Knowledge of the epidemiology, treatment and prevention of respiratory infections will assist in producing reliable estimates of the burden of ALRI to inform the preparation of national preparedness plans against influenza epidemics. At the core of these studies will be; i) a health facility based prospective surveillance of severe influenza; ii) a cohort of pregnant women and their infants and iii) a cohort of young children to estimate the burden of severe disease in these two groups of persons as a baseline for future vaccine trials. We will use these studies to document among other things the hospitalization rate of severe influenza, the burden of influenza and risk factors for severe influenza in the population, pregnant women and young children as well as evaluate case definitions for influenza and other respiratory pathogens in the DWD. In addition we will characterize influenza and other respiratory pathogens in patients with co-morbid and chronic conditions such as malaria, HIV/AIDs, Tuberculosis and Diabetes. We will also conduct studies on the immune response to influenza virus infection in the population. The studies will be initiated in the Dangme West District, one of the DSS sites in the country, and subsequently transition to the two other demographic surveillance sites in Kintampo and Navrongo in the middle belt and the northern guinea savannah respectively. We hope to obtain comprehensive data on the epidemiology, treatment and prevention of influenza and other respiratory infections in Ghana, including the hospitalization rate of severe influenza, the burden of influenza and risk factors for severe influenza. We will also obtain data to evaluate case definitions for influenza and other respiratory pathogens in the Dodowa district and characterize influenza and other respiratory pathogens in patients with co- morbid and chronic conditions such as HIV/AIDs, Tuberculosis and Diabetes. Taken together, the data from these studies will enable us to determine the relative importance of influenza and other respiratory pathogens as causes of ill health in the country as well as strengthen the capabilities of the Institute to condct training for other sites in the West African sub-region.